7.49: resolved uninitialized warnings in CUM command handler due to split() returning undef with empty modestrings.
            added new oper notice flags:

            user_opered, a local or remote user gained privileges;
            user_quit, a local or remote user disconnected;
            new_server, a new server was introduced;
            server_burst, a server began to burst information;
            server_endburst, a server finished bursting information;
            server_quit, a local or remote server disconnected;
            connection_terminated, a local connection was closed.